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Simple kinetic Monte Carlo models for dissolution pitting induced by crystal defects
1Center for Advanced Modeling and Simulation, Idaho National Laboratory, Idaho Falls, Idaho 83415-2211, USA.
The Journal of Chemical Physics
|December 3, 2008
Summary
This study enhances etch-pit growth models using faster algorithms for multiple dislocations and defects. Results show surface morphology coarsens over time, influenced by bond-breaking energies and defects, affecting pit formation and nanopipe development.
Area of Science:
- Geochemistry
- Materials Science
- Computational Modeling
Background:
- The Lasaga and Blum kinetic Monte Carlo model describes dislocation-controlled etch-pit growth.
- Previous models were computationally intensive for large surface areas.
Purpose of the Study:
- Extend the kinetic Monte Carlo model to include multiple dislocations and point defects.
- Develop significantly faster algorithms for simulating etch-pit growth.
Main Methods:
- Developed O(10^3)-O(10^4) faster algorithms for kinetic Monte Carlo simulations.
- Simulated etch-pit growth on surfaces ranging from 1024x1024 to 4096x4096 lattice sites.
- Investigated the influence of multiple line defects and bond-breaking activation energies.
Main Results:
- Surface morphology coarsens with time, especially for high bond-breaking energies.
- Low bond-breaking energies with perpendicular defects create steep-sided pits with nanopipes.
- High bond-breaking energies lead to shallow pits and suppressed pit formation via step flow.
Conclusions:
- The enhanced model accurately simulates etch-pit growth influenced by multiple defects.
- Bond-breaking energy and defect arrangement critically control pit morphology and nanopipe formation.
- Thermal fluctuations significantly impact the coarsening process in defect arrays.
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